Treatment of trees



Patented Jan. 31, 1928.

PAUL H. DAVEY, OF KENT,

OHIO, ASSIGNOR OF ONE-HALF TO JAMES A. G. DAVEY, OF

SOUND BEACH, CONNECTICUT.

TREATMENT or TREES.

No Drawing.

The present invention relates to the art of tree surgery, and more especially to repair operations, such as cutting off limbs or encavating cavities for fillings, in which the live wood of'the tree is cut, and has for its object the prevention of bleeding from the cutsurfaces. This bleeding may occur in various forms, such'as bleeding from the stump of a cut off limb, bleeding from the sa wood or. the bleeding from the heart Wood of the tree which sets up the condition commonly known among tree surgeons as slime flux, and which is particularly serious in filled cavities. Some trees, such as elms, horse chestnuts, oaks and maples, are more susceptible to slime flux than other trees. The reason why certain areas of the heart wood in certain trees will exude the flux is not definitely known. The serious ill eflects of slime flux are, however, well recognized. The flux, either before or after exuding from the wood, is acted upon by various bacteria or yeast fungi which tend to break down the solutes-into alcohols and other substances which are destructive to live tissue, so that the slime flux flowing down'over the bark of the tree will kill the bark, particularly when it comes in contact with the cambium layer. The effect of slime flux on filled tree cavities is particularly serious. The slime flux will exude over the face of the filling, disfiguring it and 'iving 0' the appearance of the trees bleeding. In

some cases it will actually prevent the cement from setting, or will wash out a part of it. It will kill the wood at the. bottom and sides of the filling. The slime flux by causing a die-back of the bark at the bottom or sides of a filled cavityexposcs an area of unprotected wood which becomes subject to infection and decay and thereby defeats the object of the cavity filling. V

The part of the heart wood of a tree forming a slime flux area appears to be water logged with the sap-like fluid which is in the heart wood. The exudation of the flux may take place immediately upon the excavating of a cavity or may occur some months thereafter. In certain regions, practically all cavities in certain trees, such, for example, as the elms, show slime flux either immediately or after a lapse of time.

Various disinfecting washes and waters proofing coatings, such as of tar, paints, varnishes, etc.,'have been applied, but have Application filed November 7, 1924. Serial. No. 748,494.

been found ineffectual to prevent ormat-erially check slime fiux. Attempts have been made to stop slime flux by char-ring the wood with a blow torch, but these also have failed. r

I have discovered that the exudation of the sap-like fluids from the heart wood which causes the slime flux may be prevented or checked by treating the slime flux area by suitable chemical reagents. In treating such slime flux areas, I first prefer to smooth off the surface and to then-treat it with a chemical reagent which will render the surface of. the wood impervious to the outward flow of the heart wood sap. This heart wood sap has a certain amount of pressure behind itwhich I have foundcan not be resisted by surface applications of paints or varnishes. i T

I have found that it is possible to make the wood surface thus impervious by treating itwith a chemical reagent which will cause a partial solution or breaking down of the cellulose of the-wood. For thispurpose,.I prefer to employ strong sulphuric acid.- Strong solutions of sulphuric acid exert a solvent action on cellulose, this being taken advantage -.of in making the tough impervious paper known as parchment paper or vegetable parchment. In applying the sulphuric acid to thesurfacc, I preferably paint on a practically pure or 66 sulphuric acid. 'One of the actions of this acid is to dehydrate the surface of the wood. I have found that within a few minutes after the strong acid has been applied to the wood, the surface appears very wet, which I believe to be due to the extraction from the wood of the moisture by the affinity of the strong sulphuric acid for it. This acid-containing moisture is then wiped off and another application: of preferably practically pure acid ismade'. The moisture in the wood is apparently sufficient to give the necessary dilution of the acid to enable it to act energetically as a solvent for the cellulose. llIoreover, because of the affinity of the acid for the moisture in the wood, the acid readily penetrates into the wood. The effect of. this second application of the acid upon the wood-is apparently similar to the application of the acid in making parchment paper, namely, to tend to dissolve or partially dissolve the wood fibres and reducethe surface to an amorphous impermeable condition. The extent .to which the acid acts upon the wood can be controlled, of course, by the amountor numberot'. applications of the acid. Ordinarily, it is found that the preliminary or dehydrating applica t ion followed by a second application is suliicient except in bad cases, which may require further applications. It is not, in general, necessary to employ enough acid to materially decompose the wood fibres, except at the very surface. ='.lhe acid,.ot' course tends to penc trate the wood and'its partially solvent action in'etta'ably. extends some little distance into the wood, particularly longitudinally of the wood fibres. The lateral penetration of the acid: appears to be rather limited, which is .anadvantage as it avoids unnecessary killing of the live tissues.

:In making the final application ofthe acid, I. prefer to rub the surface with absorbent paper toweling which itself dissolves to some extent in the acid and furnishes a dissolved cellulose. The rubbing also tends to macerate the surface libres ot' thewood and reduce them to an impermeable amorphous coating of cellulose.

lVhile'I prefer to use sulphuric acid for this purpose, other chen'iical reagents may be used, such, for example, as strongsodium or potassium hydroxide which also exert a solvent action on the cellulose, and which also have an aiiinity for water which aids in. the preliminarydrying out of thewood surface and the penctration'of the hydroxide below the surface of the wood. Sodium or potassium hydroxide may be used in more dilute solutions, and while not exerting great solvent action 011 the cellulose, nevertheless tend to swell up the cellnlose'tihres andeheck the outward exudation of the flux.

Other reagents may be employed which will convert the surface of the wood into a condition sufficiently impermeable to resist the exudation of the heart wood sap. A mixture of sulphurioand nitric acids may be employed which willdtend twconvert the surface of the wood into nitrocellulose; or mixtures of sulphuric acid with acetic-anhydride or acetic acid may be employed.

Other reagents having. a solvent-action on cellulose may be employed, for example, a concentrated solution of Zinc chloride sueh as is commonlyusedin the vulcanized librc industry,.may be used. The actionot the zinc chloride solution may be facilitated by the addition of hydrochloric acid. Also certainthiocyanates which have. an action similar to zinc chloride may be employed, il' dcsired. Also the so-called cuprannnonium solutions which are used in the processes of making artificial sill: from cellulose may he en'iployed.

Also, alter the surface has been treated and partially dehydrated by the preliminary application of a reagent, such as-sulphuric acid, co.-itings may be applied which will penetrate the dehydrated surface and seal it against the exudation ot the heart wood sap.

In case acids or hydroxidcs are used, they may be neutralizcd, it d'esired, in order to prevent possible poisoning oi? the tree thereby. For example, after the sulphuric acid has been applied andhas luul'stiliicicnt time to act upon the wood surface, the surface may betreated with a solution of sodium carbonate to neutralize at least some oi the free acid.

lVhile I have described the host reagents and methods now known to me, it is to he understood that the invention is not limited to them,-hut maybe otherwise umbodiwl within the'scope of the 'lollmv-ing claims.

I claim:

1. In the art of tree surgery, the process of repairing trees, coniprising the steps oi cutting the live wood and -applyingto the cut surface a chemical reagent which exerts a solvent action on cellulose to prevent bl od ing.

In'the art of tree surgery, the process of repairing trees, coi'i iprising the steps-oi cuttingthc live wood and applying-to the cut surface sulphuric acitl' of sullicicnt strength to'excrta solvent action on cell ulose to prevent bleeding.

3. In the art oftree-surgery,tlieproccss of repairing trees, comprising the steps at cutting the live wood and applying to the cut surface a chemical reagent which has both a dehydrating and solvent action upon the cut surface toprevcnt bleeding.

In testimony whereof I have hereunto set 1- my mm] PAULII. DAVEY. 

